The present invention relates to a hologram recording film with additional information and also pertains to a recording method therefor. More particularly, the present invention relates to a hologram recording film having a reflection type volume hologram of a three-dimensional object or the like recorded therein, together with a plane pattern, e.g. a character or an image, recorded in superimposition with the volume hologram as individual information (variable information) concerning the associated hologram. The present invention also relates to a recording method for the hologram recording film.
To record a reflection type volume hologram, a volume hologram photosensitive material, e.g. a photopolymer, is placed in close contact with or in close proximity to a reflection type volume hologram original plate for duplication, and illuminating light for duplication is applied from the hologram photosensitive material side so that reflected and diffracted light from the reflection type volume hologram original plate and the incident light interfere with each other in the hologram photosensitive material, thereby duplicatively recording a reflection type volume hologram having the same characteristics as those of the reflection type volume hologram original plate. There have heretofore been known methods of adding variable information, e.g. a serial number, to each individual hologram made by holographic duplication. Such methods are disclosed, for example, in Japanese Patent Application Nos. Hei 3-5555 and Hei 10-56470. Japanese Patent Application No. Hei 3-5555 discloses a method wherein after an image reconstructed from a hologram original plate has been recorded in a hologram film by holographic duplication, a reflecting layer is placed at the rear of the hologram film. Incident light entering the hologram film and the reflected incident light from the reflecting layer are allowed to interfere with each other in the hologram film, thereby recording individual information therein. Japanese Patent Application No. Hei 10-56470 discloses a method wherein a reflection type liquid crystal mask is provided in the vicinity of a hologram of a hologram original plate that is to be duplicated, and additional information corresponding to a reflection pattern of the reflection type liquid crystal mask is recorded on a hologram photosensitive material at the same time as the hologram to be duplicated is recorded. In addition, Japanese Patent Application No. Hei 10-56470 discloses a method wherein a reflecting region is provided on a hologram original plate in the vicinity of a hologram to be duplicated, and light is applied to the reflecting region through a transmission type liquid crystal mask to record additional information corresponding to a transmission pattern of the transmission type liquid crystal mask on a hologram photosensitive material simultaneously with the hologram.
However, the method of Japanese Patent Application No. Hei 3-5555 suffers from such problems that individual information cannot be recorded at the same time as a hologram is recorded by duplication, and the image of the individual information appears only substantially in the hologram plane. The method of Japanese Patent Application No. Hei 10-56470 involves the following problems. When a transmission type liquid crystal mask is used, the mask needs to be brought into close contact with the surface of the hologram photosensitive material during exposure process. This causes the duplicating system to become unfavorably complicated, resulting in an increase in the system cost. In addition, the process time lengthens undesirably. When a reflection type liquid crystal mask is used, it is necessary to prepare a reflection type liquid crystal mask for each hologram original plate. Hence, the original plate cost increases unfavorably.
The present invention was made in view of the above-described circumstances of the prior art.
An object of the present invention is to provide a hologram recording film having a hologram image of an object recorded in a volume hologram photosensitive material by holographic duplication and further having a hologram image of an additional information pattern, e.g. a character or an image, recorded superimposedly in the same volume hologram photosensitive material simultaneously with the holographic duplication so that the additional information pattern is reconstructable in a plane with a depth from the hologram plane, and also provide a recording method for the hologram recording film.
To attain the above-described object, the present invention provides a hologram recording film with additional information. The hologram recording film has a reflection type volume hologram recorded therein. Reflection type additional information has been recorded in the hologram recording film so as to be reconstructable simultaneously in superimposition with a reconstructed image from the volume hologram. In addition, transmission type additional information that is in mirror image relation to the reflection type additional information has been recorded in the hologram recording film so as to be reconstructable simultaneously in superimposition with the reconstructed image from the volume hologram.
In this case, the reflection type additional information and the transmission type additional information may be recorded so as to be reconstructable at a position either different from or the same as the hologram plane.
The hologram recording film may be recorded so that a full-color image is reconstructable.
In addition, the present invention provides a recording method for a hologram recording film with additional information. In this aspect, the present invention is applied to a recording method wherein a hologram photosensitive material is placed at a distance from a reflection type volume hologram original plate for forming an object image, and duplicating illuminating light for duplicating the reflection type volume hologram original plate is applied from the hologram photosensitive material side so that diffracted light from the reflection type volume hologram original plate and the duplicating illuminating light interfere with each other in the hologram photosensitive material, thereby recording a reflection type volume hologram in the hologram photosensitive material. According to the present invention, a mirror or a reflective diffuser is disposed on a part of the reflection type volume hologram original plate, and projection light projecting an additional information pattern illuminated with light from the same light source as that of the duplicating illuminating light is applied to the mirror or reflective diffuser through the hologram photosensitive material. Light reflected or diffused by the mirror or reflective diffuser and the duplicating illuminating light are allowed to interfere with each other in the hologram photosensitive material, thereby superimposedly recording a reflection hologram in the hologram photosensitive material. In addition, the projection light and the duplicating illuminating light are allowed to interfere with each other in the hologram photosensitive material, thereby superimposedly recording a transmission hologram in the hologram photosensitive material.
The above-described recording method may be as follows. The reflection type volume hologram original plate is a multi-recorded hologram original plate having a plurality of juxtaposed holograms. A mirror or a reflective diffuser is disposed on a part of each hologram of the reflection type volume hologram original plate, and projection light projecting an additional information pattern illuminated with light from the same light source as that of the duplicating illuminating light is simultaneously applied to the mirror or reflective diffuser on a part of each hologram of the reflection type volume hologram original plate through the hologram photosensitive material. Light reflected or diffused by the mirror or reflective diffuser of each hologram of the reflection type volume hologram original plate and the duplicating illuminating light are allowed to interfere with each other in the hologram photosensitive material, thereby superimposedly recording a reflection hologram in the hologram photosensitive material. In addition, the projection light and the duplicating illuminating light are allowed to interfere with each other in the hologram photosensitive material, thereby superimposedly recording a transmission hologram in the hologram photosensitive material.
In the present invention, reflection type additional information is recorded so as to be reconstructable simultaneously in superimposition with a reconstructed image from a volume hologram. In addition, transmission type additional information that is in mirror image relation to the reflection type additional information is recorded so as to be reconstructable simultaneously in superimposition with the reconstructed image from the volume hologram. Therefore, the additional information is surely visible. In addition, the additional information can be recorded so as to be reconstructable at any desired position with respect to the hologram plane. Further, because the additional information is recorded as both reflection type and transmission type additional information, it becomes easy to judge whether the hologram product is authentic or not. Furthermore, the present invention allows additional information, e.g. individual information (variable information), to be recorded by making only a simple change to the setup used for the conventional hologram duplicating method.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.